Flashlamp



May 26 1970 w. H. HAY ET AL FLASHLAMP Filed Oct. 25, 1968 BERNARD KOPELMAN WARREN H. HAY

INVENTORS MGM/M ATTORNEY United States Patent 3,514,243 FLASHLAMP Warren H. Hay, South Hamilton, and Bernard Kopelman, Salem, Mass, assignors to Sylvania Electric Products Inc., a corporation of Delaware Continuation-impart of application Ser. No. 694,275, Dec. 28, 1967. This application Oct. 25, 1968, Ser. No. 770,775

Int. Cl. F21k /02 US. Cl. 431-93 7 Claims ABSTRACT OF THE DISCLOSURE A percussively-ignited flashlamp housing a glass envelope containing a filling of fulminating material, such as shredded zirconium, and a combustion supporting gas, such as oxygen. At one end of the envelope is a press seal, through which a hollow metal tube extends, the tube being closed at its outside end and open at its inside end. A wire having the percussive material coated on the end thereof is fixedly disposed in the tube.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of our copending application, Ser. No. 694,275, filed Dec. 28, 1967 now abandoned.

FIELD OF THE INVENTION This invention relates to flashlamps, which are usually lamps having a filling of combustible material and a combustion-supporting gas in a light-transmitting envelope. In particular the invention relates to the ignition of the combustible material in such lamps by a percussive material which can be activated by a blow, such as that deliverable by a firing pin.

BRIEF DESCRIPTION OF THE PRIOR ART In a copending application of Kopelman, Ser. No. 679,142, filed Oct. 30, 1967 a photoflash lamp is disclosed in which a glass envelope is sealed about a thin-walled, deformable, hollow tube. The tube extends outside the lamp and is sealed at one end while the other end is open to the interior of the envelope. A wire is disposed inside the tube and a charge of percussive material is placed in the space between the wire and the inside of the tube. In another application of Kopelman et al., Ser. No. 662,- 756, filed Aug. 23, 1967, now abandoned and filed as a continuation, Ser. No. 751,209 filed Aug. 8, 1968, a percussive material is disclosed which can be ignited to flash the lamp.

SUMMARY OF THE INVENTION According to the present invention, we have discovered an improved construction of a photoflash lamp which will ignite upon being struck by an external force. The lamp includes an envelope which is press-sealed at one end. The lamp is filled with a combustion supporting gas such as oxygen and a fulminating material such as zirconium foil. Extending through the press seal is a hollow tube of soft metal, such as copper, or alloys, such as nickelchrome iron Number 4 Alloy or nickel-iron Number 52 Alloy.

The tube can be considered to be divided into an inner and an outer portion. The outer portion is closed at the bottom, extends beneath the press seal and contains the percussive material. The inner portion extends through the press seal, into the envelope and is open to the interior thereof. A wire, coated with the percussive material at one end, is disposed in the tube. The coated portion of the wire is disposed in the outer portion of the tube in a position where it can be effected by an external blow 3,514,243 Patented May 26, 1970 BRIEF DESCRIPTION OF THE DRAWING The figure is a cross sectional view of the photoflash lamp according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A glass envelope 1 in the form of a tube, sometimes herein called a bulb, has a sealed exhaust tubulation 2 at one end and a sealed flatly-pressed portion 3' extending from the other end. A hollow metal tube 4 extends through a flatly-pressed portion 3 and its outside end 5 is sealed by crimping, welding, soldering or the like. A high temperature solder such as silver solder can be used. A wire 6 is placed in hollow tube 4, leaving space between the two for the percussive material. The wire 6 is preferably of hard material such as steel and extends out of the hollow tube 4 into the interior of envelope 1 through the open end 7 of metal tube 4. In order to securely dispose the wire 6 and prevent it from falling out of the tube 4 if the lamp is inverted, we twist and deform the wire 6 into tortuous shape at a point along its length so that it frictionally engages the wall.

A filling of shredded zirconium foil or some other suitable fulminating material is contained within the envelope 1, in the usual flashlamp manner, together with a filling of a combustion-supporting gas, such as oxygen at a high pressure, say five atmospheres or even more.

A charge of percussive material '8 is coated upon the lower end of wire 6 and should be as small as is necessary for ignition of the fulminating material. About 1 milligram was found satisfactory in the same lamp described. The amount used extended about half-way up the tube 4. The upper end of the tube preferably extends to a position near the middle of the filling of Zirconium shreds 9 to prevent blowing all the shreds toward the tip of the bulb upon ignition.

The use of a wire 6 in the metal tube 4 serves also to keep the tube open after the percussive material has been ignited, thus preventing blow-out at the bottom. Striking the outside of the tube causes abrasive inner-particle movement of the percussive material between the tube 4 and the wire 6, which serves as an anvil. Such movement causes ignition.

The percussive material 8 which we prefer to use includes at least two components, which due to interparticle movement, will ignite when rubbed together. Intermixed within these components is a powdered combustible, incandescible metal, such as zirconium, hafnium and/or thorium. The combustible, incandescible metal can be in quantities up to about 50% by weight of the percussive material 8 and should have a particle size in the order of about 0.5 to 5 microns. When particles of the ignitable component of the percussive material are moved they ignite, and they in turn ignite the powdered combustible material, which in turn incandesces and travels along the tube 4 and spews into the body of the envelope 1. The incandescent particles ignite the shredded fulminating metal and the lamp flashes.

It is apparent that modifications and changes may be made within the scope of the instant invention. It is our intention however only to be limited by the scope of the appended claims.

As our invention, we claim:

1. A photoflash lamp including a glass envelope sealed at one end and containing a filling of shredded fulminating metal and oxygen, a tube of deformable metal extending through said seal, said tube being closed at the outer end and open at its inner end into the interior of said envelope, a wire extending into said tube along the length thereof, a percussive material disposed about a portion of said wire, said wire being deformed so as to abut against the inside of said tube and retain said wire there'- in.

' 2. The lamp according to claim 1 wherein said percussive material extends less than about half way up the external length of said tube.

3. The lamp according to claim 1 wherein the percussive material includes up to about 50% by weight of a powdered combustible incandescible metal.

4. The lamp according to claim 2 wherein the percussive material includes up to about 50% by weight of a powdered combustible incandescible metal.

5. The lamp according to claim 1 wherein the wire is deformed into a tortuous shape.

6. The lamp according to claim 2 wherein the wire is deformed into a tortuous shape.

7. The lamp according to claim 4 wherein the wire is deformed into a tortuous shape.

References Cited FOREIGN PATENTS 431,953 7/1935 Great Britain. 

